The present invention relates to the devices for changing to a transverse direction the longitudinal direction of movement of rod-like articles, particularly cigarettes.
More particularly, the invention is concerned with the devices for sequentially transferring cigarettes or cigarette pairs from a rectilinear, preferably horizontal path, so-called "longitudinal", along which the cigarettes are moved forward in a file in which they are axially aligned, to a rotary fluted drum with its axis of rotation being parallel to the said rectilinear horizontal path, the transferred cigarettes being successively deposited, parallelly arranged side by side, onto said drum in a row, which is transversal with respect to the cigarette file moving along the longitudinal path.
In the known transferring devices of the kind as disclosed in the preceding paragraph, the transfer of the cigarettes from the longitudinally moving file of axially aligned cigarettes to the transversally arranged cigarette row is sequentially effected by means of pneumatic pick up or suction heads being timely moved in regular succession. The suction heads are connected with a positively driving means causing them to translate parallelly to themselves along a closed path which is operatively associated with a station for picking up the cigarettes from the cigarette file moving along the longitudinal path, as well as with a station for the delivery of the picked up cigarettes onto a movable means for supporting the transverse cigarette row, such as the said rotary fluted drum.
At the said cigarette pick up station, each one of the pneumatic pick up or suction heads will graze the cigarette file, while at the cigarette delivery station each suction head will pass tangentially to the fluted drum.
Still at the said station in which the cigarettes are picked up from the cigarette file, the suction heads are so driven by the said driving means as to skim longitudinally the said file at a tangential speed which is preferably maintained slightly higher than the speed at which the cigarette file is running; whereas, at the station in which the cigarettes are delivered, the now transversal speed of the suction heads must substantially coincide with the peripheral speed of the fluted drum.
In these known transferring devices, while a suction head is transferring one cigarette from the pick up station to the delivery station, by translating along the corresponding section of the said closed path along which the suction heads are moved, the suction head speed in the axial direction of the picked-up cigarette will gradually increase, while its speed in the transverse direction of the picked-up cigarette will correlatively increase.
In order to prevent the thus transferred cigarettes from becoming deteriorated owing to a loss of tobacco from their ends during the cigarette transfer, any acceleration and deceleration to which the cigarettes will be subjected should be reduced to the minimum possible value.
The afore-disclosed known transferring devices, such as those of the kind with an epicyclical transfer path, meet with the requirement of limiting any acceleration and deceleration as undergone by the cigarettes being transferred, so far as the axial speed at which the file of the to-be-transferred cigarettes runs, does not exceed the limit of a certain peak value that is dependant from the processing rate of the cigarette-packing machine.
However, these known transferring devices are complicated and costly in construction, and often they are even noisy, since they involve the use of epicyclic trains, sometimes also with internal gears.
A transferring device of the above kind is also known, in which the said suction heads for picking up the cigarettes from the cigarette file moving along a longitudinal path and for delivering them onto the rotary fluted drum are led to translate over an elliptical path which at one extremity of its minor axis is tangent to the file of cigarettes to be picked up, while at one extremity of its major axis it is operatively associated with the fluted drum, in correspondence of the station for the delivery of the transferred cigarettes thereonto.
By adopting such an elliptical path for the suction heads, any dynamic stress on the cigarettes, resulting from excessive acceleration and deceleration in the transfer movement of the suction heads, will be considerably reduced owing to the fact that after a cigarette has been picked up by one of the suction heads, the speed of said head in the axial direction of the picked-up cigarette will decrease very gradually along the elliptical path, while its speed in the direction perpendicular to the picked up cigarette will increase at an accordingly gradual rate.
However, in the case a very reduced spacing should have to be provided between the suction heads, the fact that the suction heads are caused to translate in succession along an eliptical path would involve certain drawbacks.
Actually, in such a case, the swinging arms carrying the suction heads must be made with an angled shape in order to prevent them from interfering with each other during their movement along an elliptical path, which complicates the construction of said arms due to the gearings that must be provided in the same for maintaining the orientation of the respective suction heads unchanged during their motion of translation.
When a transferring device of the above kind is required, in which the spacing between the swinging arms carrying the suction heads needs to be a very reduced one, it is expedient to provide a kind of transferring device in which the swinging arms are driven along a substantially circular closed path.
In a known transferring device of this kind, in which the arms carrying the suction heads are driven along a substantially circular closed path, a driving means--that is driven at a constant speed, imparts to said arms in succession a rotary motion with a periodically varying speed.
Such a periodically varying rotary motion as imparted to every one of the arms carrying one suction head, is intended for cyclically compensating the speed at which the respective suction head is translating, so as to adapt it to the cigarette pick up and delivery operations, as well as to the conditions of the cigarette transfer between the pick up and the delivery stations.
However, this kind of transferring device in which the interspaced arms carrying the suction heads are jointly moved along a constrained circular path and are each cyclically driven into a phased rotary motion at a periodically varying speed as imparted by a driving means run at a constant speed, although being theoretically possible, cannot be practically carried out because of the batch-or fan-like arrangement of said arms.
An improvement to the type of transferring device briefly disclosed in the two preceding last paragraphs, was made by providing two axially offset, equally sized parallel discs, of which one of the discs (the driving disc) entrains the driven other disc in rotation through a set of like crank-and-connecting-rod linkages regularly arranged in a circle. These linkages couple the two discs with each other in a kinematically coordinated manner, and comprise each the shaft of one respective cigarette picking up and delivering suction head, whereby the said head will be driven into a motion of translation along a circular path at the constant angular speed as dictated by the said suitably operated driving disc.
Into the common constant rate of reciprocation of the circularly arranged linkages, resulting from the crank-and-connecting-rod type connections between the two equally sized, axially offset discs, a speed adjustment factor will be periodically introduced at every revolution of said discs. The said speed adjustment factor consists in the fact that within the limits of the rotation as imparted to the linkages by the said discs, the oscillation of every one of the linkages is constrained by at least one fixed circular cam arranged concentric with at least one of the discs, and which suitably modifies the cigarette-grazing speed of the pneumatic pick up or suction head being associated to that one linkage, at the moment this very head has to pick up one cigarette from the longitudinally moving file of axially aligned cigarettes.
In the said known transferring device provided with linkages in form of cranks and connecting rods, which are driven between two axially offset discs, these linkages promote the parallel translation of the suction heads along a circular closed path, as well as the adjustment of the suction heads speed at the time these heads are picking up a cigarette from the cigarette file.
However, the said device presents a rather complicated structure, while a great accuracy is required in the construction of same. Moreover, this device is rather cumbersome, since its operation is based on axially offset discs.
The present invention proposes a sequentially transferring device with its speed being self-compensated, for changing into a transversally arranged row a file of axially aligned rod-like articles moving along a rectilinear, preferably horizontal path, so-called "longitudinal", particularly for regularly transferring onto a rotary fluted drum the cigarettes axially aligned in a file moving along the said longitudinal path. The said transferring device is provided with a number of star-like arranged arms being driven into a positive swinging motion, which respectively carry one same pneumatic pick up or suction head, and which are pivotably mounted onto a rotary drum driven into a positive rotation at a constant speed. The said drum constitutes also the planet carrier for a sun-and-plural planets motion being arranged in such a manner as to entrain in succession the said suction heads into a regular motion of translation along a substantially circular path. The said positively swinging arms are associated each to the correlated one of the positively driving reciprocating means being each operatively interlocked with one of the planets of the said sun-and-planets motion, and being cyclically driven thereby into an oscillatory motion, phased and synchronized with the circular motion of translation of the suction heads. Thus, at every revolution of the planet drum being rotated at a constant speed, a swinging motion of every suction head-carrying arm will be set over in sequence to the motion of translation of the respective suction head, so that the speed thereof will be properly modified and adapted to the cigarette pick up and delivery operations, as well as to the cigarette transfer from the pick up to the delivery station.